Polyesters and polyurethane foams from di-and tri-(beta-carboxyethyl) isocyanurates and process for preparing them



POLYESTERS AND POLYURETHANE FOAMS FROM Dl- AND TRI-(BETA-CARBOXYETHYL)ISOCYANURATES AND PROCESS FOR PRE- PARING THEM Alexander Sadle,Petersburg, Va., assignor to Allied Chemical Corporation, New York,N.Y., a corporation of New York No Drawing. Continuation-impart ofapplication Ser. No. 814,671, May 21, 1959. This application Dec. 11,1963, Ser. No. 329,866

Claims. (Cl. 26075) This invention relates to new polyester resins andto polyurethane products prepared therefrom.

This application is a continuation-in-part of my application Serial No.814,671 filed May 21, 1959, now US. Patent No. 3,235,553.

In the above application there are described diand tri-(beta-c'arboxyethyl)isocyanurates and their esters which are prepared byhydrolyzing diand tribeta-cyanoethyl isocyanurates to thebeta-carboxyethyl derivatives which can then be esterified with alcoholsto form the corresponding esters.

In accordance with the present invention the diandtri-(beta-carboxyethyl)isocyanurates or their lower alkyl esters arereacted with polyhydric alcohols to produce useful polyesters. Theresulting polyesters are useful in the preparation of fibres and ascoating resins. The new polyesters are also useful as starting materialin reactions with organic diisocyanates for the production ofpolyurethanes, particularly rigid urethane foams suitable for thermaland structural insulation. It is, therefore, a feature of the presentinvention to provide new polyurethane products and a process forpreparing them by reacting diand tri-(beta-carboxyethyl) isocyanurate ora lower alkyl ester thereof with a polyhydric, preferably dihydric,alcohol having from 2 to 12 carbon atoms, and reacting the resultingpolyester with an organic diisocyanate.

In carrying out the process according to my invention the diandtri-(beta-c'arboxyethyl)isocyanurates as described in my parentapplication above referred to or their lower alkyl esters are condensedwith polyhydric alcohols, particularly with alkylene glycols, or diortrialkylene glycols containing from 2 to 12 carbon atoms.

The reaction of a glycol with di-(beta-carboxyethyl) isocyanurate or alower alkyl ester thereof produces a linear polyester consisting of thefollowing repeating units,

OOCCHzCH2I| I and terminal hydrogen, hydroxyl, glycol or carboxyethylisocyanurate units.

Reaction of a polyhydric alcohol withtri-(beta-carboxyethyl)isocyanurate, or ester thereof, produces apolyester which may be either linear or cross-linked, and whosecomposition will vary with proportions of reactants used and withreaction conditions.

The condensation reaction is carried out by heating the reactants atelevated temperatures, for example, between about 180 C. and about 240C., and in the case of the lower alkyl esters of diandtri-(beta-carboxyethyl)isocyanurates, preferably in the presence of atransesterification catalyst such as antimony trioxide (Sb O lead oxide(PbO), tin caprylate, zinc caprylate or lead naphthenate. Suitablepolyhydric alcohols which form polyesters with diandtri-(beta-carboxyethyl)isocyanui d States Patent 0 ice rate include thealkylene glycols, such as ethylene glycol, propylene glycol, butadiol-1,4 or -1,2, pentamethylene glycol, hexamethylene glycol, decamethyleneglycol and dodec'amethylene glycol, as well as diethylene glycol,glycerol, polyethylene glycols, etc.

The resulting polyesters are characterized by excellent adhesion tometal and other substrates and have high flexibility and toughness whenapplied as coating compositions. They are also resistant to elevatedtemperatures and thus are suitable for laminating metals and asbestossheets and for impregnating glass cloth and asbestos tapes.

In accordance with another embodiment of my invention, the abovepolyesters are converted into polyurethanes by reaction with organicdiisocyanates and particularly into rigid foams by such reaction,preferably using the customary additives for such reactions; namely, acatalyst such as an organic amine, water and a foaming agent such as asurface active agent, including the alkyl sulfates and sulfonates, alkylaryl sulfonates, fatty acid amides, alkyl amido sulfates, alkyl arylpolyether alcohols, etc. Water may be omitted and a gaseous blowingagent such as a fluorocarbon may be used instead of the in situgenerated CO produced by contact of water with an excess ofdiisocyanate.

The organic diisocyanates generally may be employed in this reaction,including 4,4-diphenyl diisocyanate, 4,4- diphenylene methanediisocyanate, di-anisidine diisocyanate, 4,4-toldene diisocyanate,1,5-naphthalene diisocyanate, 4,4'-diphenyl ether diisocyanate,p-phenylene diisocyanate, the meta tolylene diisocyanates such as 2,4-and 2,6-tolylene diisocyanates or mixtures thereof.

In preparing the foamed polyurethane, the polyester is mixed withbetween about 10 parts and about 50 parts of an organic diisocyanate,per parts of polyester (parts are by weight). To this mixture may beadded a small proportion of an amine catalyst, for example, betweenabout 05 part and about 3 parts per 100* parts of polyester; betweenabout 1 part and about 5 parts water and between about 0.5 part andabout 5 parts of a surface active agent or detergent to function as afoaming agent.

The resulting rigid foams have many uses and are especially adapted forthermal insulation, as in refrigerators, etc.

The following specific examples further illustrate the invention:

Example 1' Tri-(beta-carboxyethyl)-isocyanurate, 1 mol, andhexamethylene glycol, 9 mols, were mixed and heated in the presence of0.1% by weight of Sb O' at 180-200 C. at atmospheric pressure for sevenhours. During the ester interchange which took place, 77% of thetheoretical amount of ethanol was recovered, indicating production ofthe hexamethylene glycol polyester to at least about this extent. Next,72.8% of the excess hexamethylene glycol was removed at 141 C./0.22 mm.Hg.

Fifty parts of the hexamethylene glycol polyester thus produced wasmixed with 17 parts of toluene diisocyanates (Naccon'ate 80) andstirred. To this was added a solution containing 1 part of N-methylmorpholine (catalyst), 2 parts water, and 1 part of detergent. Foamingwas almost instantaneous. The foam was heated in an oven for 45 minutesat C. to complete the cure.

The finished foam was white, rigid and resistant to mechanical shock.

When the process of Example 1 is repeated employingdi(beta-carboxyethyl)isocyanurate, 1 mol, and decamethylene glycol, 2mols, a linear polyester is obtained suitable for use in coating andlaminating compositions.

Example 2 Tri(beta-carboxyethyl)isocyanurate, 34.5 parts (0.10

mole) were mixed with 38.94 parts (0.33 mole) of hexamethylene glycoland heated at temperatures of 235 C. to 240 C. in a nitrogen atmospherewith stirring for about 11 hours. The reaction mixture was then allowedto cool overnight, when heating was resumed and continued for anadditional 4 hours. At this point an 'acid number of 20.4 mg. KOH/ gm.of sample indicated the acid groups were about 89% reacted. Theresulting polyester was subjected to the following tests:

(1) Copper wire (A.W.G. 18 gauge, hand drawn) was coated with six layersof the polyester diluted with 50 volume percent cresylic acid. Each coatwas cured 'at 240 C. for 4 minutes. The final product had an irregularbut continuous coat.

(2) Substantially the same results were obtained with undilutedpolyester.

(3) Steel panels were coated with the polyester diluted with 50 volumepercent methyl Cellosolve acetate (2-methoxyethylacetate). The solventwas evaporated at 125 C. and then cured at 240 C. for one hour. Thecoating was flexible and showed perfect adhesion to the steel panelswhen subjected to the Gardner conical mandrel bent test (Serial No.281). The film did not crack when subjected to both front and backimpact tests.

Another steel panel coated in the same manner gave a Sward hardnessvalue of approximately 12 and a standard pencil scratch of 4H. Thecoating did not flake ofi when attempts were made to pry the coatingloose.

The polyester has excellent adhesion 'and flexibility. It is toughrather than hard. The polyester withstands moderately high temperatureand is applicable for laminating metals and asbestos sheets as well asfor impregnating glass cloth and asbestos tapes.

While the above describes the preferred embodiments of the invention, itwill be understood that departures may be made therefrom within thescope of the specification and claims.

I claim:

1. A resinous polyester of tri-(beta-carboxyethyl)isocyanurate and apolyhydric alcohol.

2. A resinous polyester of tri-(beta-carboxyethyl)isocyanurate or alower alkyl ester thereof and a polyhydric alcohol.

3. A resinous polyester of di-(beta-carboxyethyl)isocyanurate and apolyhydric alcohol.

4. A polymeric resinous polyester reaction product of a member selectedfrom tris(beta-carboxyethyl)isocyanurate and lower alkyl esters thereofand a polyalkylene glycol containing from 2 to 12 carbon atomsinclusive.

5. A linear polymeric resinous polyester consisting of the followingunits References Cited UNITED STATES PATENTS 2,838,511 6/1958 Kogon260-75 X 3,061,591 10/1962 Roth 260-75 2,921,916 1/1960 Harrison et al.260-25 3,054,760 9/1962 Worsley et a1 260--2.5

DONALD E. CZAJA, Primary Examiner.

H. S. COCKE-RAM, G. W. RAUCHFUSS, J. J.

KLOCKO, Assistant Examiners.

1. A RESINOUS POLYESTER OF TRI-(BETA-CARBOXYETHYL)ISOCYANURATE AND APOLYHYDRIC ALCOHOL.